1. Field of the Invention
The present invention concerns a spillage recovery device and its method of use and, in particular, relates to the recovery of oil spills upon water.
2. Related Art
Although the present invention can be used to recover any floating material upon water, it is particularly well-suited to the recovery of oil spills on water. Oil spillage can result from several sources such as accidental discharge from ships, run-off from land, shipwrecks, oil well blowouts, and the like. The conventional method of recovery of oil spillage on the water is the use of a boom curtain that is deployed around the oil spill. The curtain is stored in a folded condition and upon deployment, a flotation collar is inflated and then the curtain is pulled around the oil spill. Such a boom curtain is disclosed in U.S. Pat. No. 5,197,821, issued to Cain et al on Mar. 30, 1993 and entitled xe2x80x9cLightweight, Rapid Deployment Oil Spill Containment Boomxe2x80x9d. A suction system removes the oil after it is confined to an area within the boom and the recovered oil is placed in a storage container. The confined oil can also be treated with sulfur which tends to hold the oil together so that it can be collected by a system having scoops as disclosed in U.S. Pat. No. 3,844,941, issued to Jones on Oct. 29, 1974 and entitled xe2x80x9cUse of Sulfur for Combatting Oil Spillsxe2x80x9d. Another major source of oil spillage is oil well blowouts. Both U.S. Pat. No. 3,664,136, issued to Laval, Jr., et al on May 23, 1972 and entitled xe2x80x9cCollecting Device for Submarine Oil Leakagexe2x80x9d, and U.S. Pat. No. 4,318,442, issued to Lunde et al on Mar. 9, 1982 and entitled xe2x80x9cMethod and Apparatus for Controlling an Underwater Well Blowoutxe2x80x9d, disclose systems for collecting oil leaking from underwater sources.
The aforementioned U.S. Pat. No. 5,197,821 discloses a boom curtain having a flotation chamber and a ballast chamber with a curtain connecting therebetween. The boom curtain can be deployed by means of an airplane, helicopter, or ship. Upon deployment, the flotation chamber is inflated by compressed air bottles and/or other compressed air sources. The ballast chamber fills with water.
U.S. Pat. No. 3,844,941 discussed above discloses a system of collecting oil from an oil spill where sulfur powder or hot sulfur is sprayed on the oil spill and acts to entrap the oil. The oil can then be collected by a mechanical scoop. The sulfur can be applied to the oil spill by helicopter or ship which is the preferred method because of its large capacity for storage.
U.S. Pat. No. 4,318,442 discussed above discloses an apparatus that is lowered over an underwater oil well blowout having both gas and oil therein. A cylindrical hollow body has a base ring as ballast. The top of the body is attached to a frusto-conical top with a chimney thereon. Vent ports in the side of the body allow water to move in and out as the volume of gas changes in the top. The gas is removed from the top by means of a conduit and can just be vented or recovered. The body has an oil outlet located in the oil layer therein and the oil can be removed by pump to a storage container located on a ship. The apparatus is lowered by crane to the site of the oil well.
U.S. Pat. No. 3,664,136 discussed above discloses another device for collecting oil leaking from underwater. A pair of ring-shaped envelopes provides a container for holding a ballast material that keeps the device located about the source of oil. A frusto-conical shaped shroud is connected to the envelopes. The upper part of the shroud has a smaller envelope thereabout to provide a desired form to the device. An oil removal conduit is located at the top of the shroud.
Although these devices do provide a means for collecting oil, they do not provide a means for immediately reducing the area of the oil spill and collecting the oil therein.
In one broad aspect, the present invention relates to a recovery device for containing a material floating on the surface of a liquid. The recovery device includes a shroud having an open top and an open bottom, the open top having an area which is smaller than the area of the open bottom. The device being of sufficient weight causes the shroud to sink in the liquid such as water to a collection position in which the open bottom is submerged below, and the open top is at or above, the surface of the liquid. The device is positioned with the open bottom at the surface of the liquid and encircling at least a portion of the floating material and then the shroud is allowed to sink to its collection position collecting the floating material encircled by the open bottom into the smaller area of the open top, thereby facilitating collection of the floating material.
According to another aspect of the invention, the recovery device may also include a collar attached to the open top, a skirt attached to the open bottom and ballast weights to further aid in sinking the shroud about the floating material. The collar provides an attachment point between the shroud and a deployment carrier, such as a ship or helicopter, and also provides an area to collect the floating material. The skirt may provide stiffness to the open bottom and as an attachment point for the ballast weights. The recovery device is transported to a location of the floating material to be collected and the open bottom is then lowered over at least a portion of the floating material and as it sinks, the floating material is forced into the smaller area of the open top where it is collected.
In accordance with another aspect of the invention, the recovery device for containing floating material such as oil on a water surface has a releasable holding device connected to the collar and to a deployment carrier when in use. The releasable holding device is connected to the recovery device which has a shroud with an open area in the open top where the floating material is collected. The flexible shroud is essentially a truncated cone with an open top and an open bottom. The shroud provides a solid flexible wall between the open top and the open bottom. A skirt is connected to the bottom of the shroud and an expandable device is connected to the skirt. In a transport mode, the shroud may be essentially cylindrical in shape and, after the expandable device operates on the skirt, the skirt opens to have an open area therein of substantially greater area than the open area of the collar. In order to force the floating material into the collar open area, ballast weights are attached about the skirt and the ballast is of sufficient weight so as to cause the skirt to sink in the water about the floating material whereby the floating material in the skirt open area is reduced from such area to the collar open area of substantially less size for collecting the floating material therefrom.
Yet another aspect of the present invention provides a recovery device that may be a frustum-shaped shroud although the bottom may be circular or polygonal in shape and the top is attached to a collar having an open top.
Still another aspect of the present invention provides a recovery device that collects a large diameter of spillage and reduces it to a much smaller diameter for recovery.
The present invention may also provide a recovery device that may be repeatedly used.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the pertinent art from the following detailed description of a preferred embodiment of the invention and the related drawings.